HLSL Compiler and d3dcompiler_xx.dll

[Jason Green]

On Apr 14, 2010, at 1:48 PM, Matijn Woudt wrote:

>> I think you want to test if the compiled shader works instead of the
>> exact bytecode. Generating the same bytecode is probably way too hard,
>> fragile to test, and most likely not worth the effort.
> 
> I think I should go for exact bytecode as long as it is possible, it's
> the only way we can be sure the implementation is 100% right for each
> test case.

FYI, we encountered a game a while back which used a few shaders that depended on being compiled with a particular version for d3dx9_##.dll.  There was a compiler bug which the game engine knew about and accounted for.  If you tried to use the compiled shader from a newer d3dx9_##.dll, then the rendering wouldn't look quite right on certain objects.

So, there's one argument for identical bytecode compatibility, but it's likely that very few apps will exhibit behavior like this.